JPH04161356A - Image formation device - Google Patents

Abstract

PURPOSE:To improve density contrast by applying specific voltage to first and second electrode layers provided respectively on a toner supply side and on an opposite side of an insulating layer having apertures at the time of an OFF signal. CONSTITUTION:Apertures 15 are arranged in a row opening to an insulating layer 16. A first electrode layer 17 is provided on the insulating layer 16 on the side of a brush roller 7. A second electrode layer 18 is provided on the insulating layer 16 around the apertures on the top surface of the layer independently. In a recorder 2, a toner T is made to pass the brush roller 7 by a supply roller 10, electrified positively so as to become cloud, supplied to an aperture electrode 8, attracted by the first electrode layer 17 connected to a power source E1 having voltage -100V, and receives a Coulomb's force directed to the first electrode layer 17 (-100V) from the second electrode layer 18 (0V) when the aperture electrode 8 is in OFF due to a voltage applied to the second electrode layer 18 from a signal source S. Thus, the toner will not pass through the apertures 15 in the OFF time, so that a printout having sufficiently high density contrast can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus applied to copying machines, printers, displays, and the like.

[Prior Art] A conventional image forming apparatus includes a toner clouder that supplies a cloud of charged toner near an aperture electrode, and an aperture electrode and a counter electrode that modulate the flow of toner from the toner cloud. . This aperture electrode consists of an insulating layer with a large number of apertures, a first electrode layer, and a large number of second electrode layers.The first electrode layer is provided on the toner crowder side of the insulating layer, and the second electrode layer is independently provided around the aperture on the opposite surface of the insulating layer to the surface on which the first electrode layer is provided. The counter electrode attracts and holds a support such as paper (hereinafter referred to as a medium), and is arranged opposite to the aperture electrode! be done.

The first electrode layer is connected to ground and the second electrode layer is connected to a respective signal source. Further, a toner flying voltage (a voltage with a polarity opposite to that of the toner; for example, a voltage with a negative (-) polarity when a positively (+) charged toner is used) is applied to the counter electrode.

[Problems to be Solved by the Invention] However, when driving the image forming apparatus as described above,
Sufficient density contrast could not be obtained for print output.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an image forming apparatus that can obtain print output with sufficiently high density contrast.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an aperture electrode that is connected to a signal source and modulates and controls charged toner, and a toner supply body that supplies the toner near the aperture electrode. In the image forming apparatus, the aperture electrode includes an insulating layer having an opening, a first electrode layer provided on the toner supplier side of the insulating layer, and a second electrode layer provided on the opposite side of the insulating layer. and the first electric field is configured such that, when the signal is OFF, an electric field is generated in the opening so that the charged toner generates a Coulomb force in the direction of the toner supply body.
, a voltage is applied to the second electrode layer.

[Function] According to the above configuration, when the signal is ON, the Coulomb force directed toward the charged toner or the medium is transferred to the OF of the signal.
When F is applied, a voltage is applied to the first and second electrode layers so that the electric field is such that the charged toner generates a Coulomb force in the direction of the toner supplier, and when it is ON, a large amount of toner is applied to the support. Furthermore, when the toner is turned off, almost no toner adheres to the medium.

Embodiment Embodiments of the image forming apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a toner jet recording apparatus according to this embodiment. The toner jet recording device 1 is composed of a recording section 2 and a heat fixing section 3, and on the side of the toner jet recording device 1 there is an insertion slot 4 for a sheet of paper (hereinafter referred to as medium P) on which an image is recorded. and an outlet 5 are provided. In the recording section 2, an image or the like is recorded on a medium P such as plain paper inserted through the insertion slot 4, and in the thermal fixing section 3, the image or the like on this medium is fixed. Furthermore, the medium P is sent to the ejection port 5 via the guide 6.

The recording unit 2 is composed of a rotatable brush roller 7, an aperture pole 8, and a counter electrode 9.

Around the brush roller 7, a supply roller 10, a layer thickness regulating member 11, and a scraping member 12 are provided in contact with the brush roller rough, respectively, in accordance with the rotating direction of the brush roller 7. The brush roller 7 is connected to ground, and the supply roller 10 is covered by a toner case 13, in which toner T is stored.

Above the brush roller 7, the aperture electrode 8 is provided. FIG. 2 is a detailed view of the aperture electrode 8, which is composed of a large number of apertures 15, an insulating layer 16, a first electrode layer 17, and a large number of second electrode layers 18. The apertures 15 are opened in the insulating layer 16 and arranged in a line, the first electrode layer 17 is provided on the brush roller 7rpJ of the insulating layer 1w16, and the second @ pole layer 18 is arranged around the apertures 15 on the upper surface of the insulating layer 16. be established independently. The first electrode layer 17 is connected to one hundred DC power sources E1, and the plurality of second electrode layers 18 are connected to a plurality of signal sources S, respectively.

On the opposite side of the brush roller 7 with this aperture electrode 8 in between, the counter electrode 9 is provided with a certain space from the aperture t [i8.
The paper enters the space, is sent via the guide 6 and a pair of auxiliary rollers 19, and passes through the space. This counter electrode 9 is connected to a power source E2 (-1KV). By applying this voltage, the toner T that has passed through the aperture 15 of the aperture electrode 8 is moved and adsorbed onto a#P. The heat fixing section 3 includes a roller 20 having a heat source and a press roller 21. The heat roller 20 and the press roller 21 are arranged so that the medium P can pass between them.

Next, using the same figure, the toner knit recording section according to this embodiment! Explain the operation. The medium P inserted through the insertion port 4 is conveyed to the recording section 2 . In the recording unit 2, the toner T is supplied to the brush roller 7 by the supply roller 10. At this time, the toner T rubs while contacting the supply roller 10 and the brush roller 7, for example, a positive (+)
is charged with electricity. The positively (+) charged toner T is carried by the brush roller 7. Then, the layer thickness regulating member 11 scrapes off the toner T supplied to the brush roller 7 in excess. As a result, the brush roller roller 7
A uniform toner layer is formed on top. Then, the brush roller 7 is scratched by the scraping member 12 near the aperture electrode 8, and when the brush returns to its original position due to its elasticity, an appropriate amount of toner T carried by the brush jumps up.

As a result, the toner T is supplied to the aperture electrode 8 in the form of a cloud.

The cloud of positively charged toner T is -10
The flow of the toner T is modulated by the voltage applied to the second electrode layer 18 of the aperture electrode 8 from the signal source S, which is attracted to the first electrode layer 17 connected to the 0V power source E1.

For example, as shown in FIG. 3, -300V is applied to the second electrode layer 18 as a toner passing voltage, and 0V is applied as a toner shielding voltage. As a result, the charged toner 3
0 indicates the first electrode layer 17 when the aperture electrode 8 is ON.
(-100V) toward the second electrode layer 18 (-300V), and when it is OFF, the second electrode layer 18
(OV) to the first tli layer 17 (-100V).

Since the charged toner 30 does not pass through the aperture 15 when it is OFF, it is possible to obtain a print output with a sufficiently high density contrast later.

Next, the positively (+) charged toner 30 modulated by the negative power supply E2 connected to the counter electrode 9 flies toward the pole 9 and is guided to the guide 6 and the pair of auxiliary rollers 19. It is attracted to the medium P that has been flowing.

Thereafter, the medium P is conveyed to the heat fixing section 3, where the image on the medium P is fixed by being brought into pressure contact with the heat roller 20 and the press roller 21. Since this fixing method is a numerical method, detailed explanation will be omitted. Finally, the imaged medium P is moved to the guide 6
is conveyed to the take-out port 5 and taken out.

Note that the present invention is not limited to the embodiments described above, and various changes can be made without departing from the spirit thereof.

For example, as shown in FIG. 4, the first electrode layer 17 may also be provided independently around the aperture 15 similarly to the second electrode layer 18, and by adopting this configuration, the power 300V only) can be reduced.

[Effects of the Invention] As is clear from the detailed description above, according to the present invention,
By controlling the electric field in a part of the aperture, the movement of toner toward the medium side is prevented when the signal is OFF, so that print output with sufficiently high density contrast can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of a toner jet recording device according to an embodiment of the present invention, Fig. 2 is a perspective view of an aperture electrode provided in the toner jet recording device, and Fig. 3 shows the aperture in the ON/OFF state. FIG. 4 is a partial sectional view showing the ON/OFF state of the aperture electrode of another embodiment. 7... Brush roller (toner supply section), 15... Aperture (opening), 16... Insulating layer, 17... First electrode layer, 18... Second electrode layer, 8...・Aperture electrode, T...toner. Applicant: Brother Industries, Ltd.

Claims (1)

[Claims] (1) In an image forming apparatus including an aperture electrode that is connected to a signal source and modulates and controls charged toner, and a toner supply body that supplies the toner near the aperture electrode, the aperture electrode has an opening. a first electrode layer provided on the toner supplier side of the insulating layer, and a second electrode layer provided on the opposite surface of the insulating layer,
At times, a voltage is applied to the first and second electrode layers so that an electric field is generated in the opening that causes the charged toner to generate a Coulomb force in the direction of the toner supplier. Forming device.